From 3171a0305d62e6627a24bff35af4f997e4988a80 Mon Sep 17 00:00:00 2001 From: Atsushi Nemoto Date: Fri, 29 Sep 2006 02:00:32 -0700 Subject: [PATCH] simplify update_times (avoid jiffies/jiffies_64 aliasing problem) Pass ticks to do_timer() and update_times(), and adjust x86_64 and s390 timer interrupt handler with this change. Currently update_times() calculates ticks by "jiffies - wall_jiffies", but callers of do_timer() should know how many ticks to update. Passing ticks get rid of this redundant calculation. Also there are another redundancy pointed out by Martin Schwidefsky. This cleanup make a barrier added by 5aee405c662ca644980c184774277fc6d0769a84 needless. So this patch removes it. As a bonus, this cleanup make wall_jiffies can be removed easily, since now wall_jiffies is always synced with jiffies. (This patch does not really remove wall_jiffies. It would be another cleanup patch) Signed-off-by: Atsushi Nemoto Cc: Martin Schwidefsky Cc: "Eric W. Biederman" Cc: Thomas Gleixner Cc: Ingo Molnar Cc: john stultz Cc: Andi Kleen Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Richard Henderson Cc: Ivan Kokshaysky Acked-by: Russell King Cc: Ian Molton Cc: Mikael Starvik Acked-by: David Howells Cc: Yoshinori Sato Cc: Hirokazu Takata Acked-by: Ralf Baechle Cc: Kyle McMartin Cc: Heiko Carstens Cc: Martin Schwidefsky Cc: Paul Mundt Cc: Kazumoto Kojima Cc: Richard Curnow Cc: William Lee Irwin III Cc: "David S. Miller" Cc: Jeff Dike Cc: Paolo 'Blaisorblade' Giarrusso Cc: Miles Bader Cc: Chris Zankel Acked-by: "Luck, Tony" Cc: Geert Uytterhoeven Cc: Roman Zippel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/timer.c | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-) (limited to 'kernel/timer.c') diff --git a/kernel/timer.c b/kernel/timer.c index a2cb1ecb1b2..4f55622b0d3 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -1222,10 +1222,8 @@ static inline void calc_load(unsigned long ticks) unsigned long active_tasks; /* fixed-point */ static int count = LOAD_FREQ; - count -= ticks; - if (count < 0) { - count += LOAD_FREQ; - active_tasks = count_active_tasks(); + active_tasks = count_active_tasks(); + for (count -= ticks; count < 0; count += LOAD_FREQ) { CALC_LOAD(avenrun[0], EXP_1, active_tasks); CALC_LOAD(avenrun[1], EXP_5, active_tasks); CALC_LOAD(avenrun[2], EXP_15, active_tasks); @@ -1270,11 +1268,8 @@ void run_local_timers(void) * Called by the timer interrupt. xtime_lock must already be taken * by the timer IRQ! */ -static inline void update_times(void) +static inline void update_times(unsigned long ticks) { - unsigned long ticks; - - ticks = jiffies - wall_jiffies; wall_jiffies += ticks; update_wall_time(); calc_load(ticks); @@ -1286,12 +1281,10 @@ static inline void update_times(void) * jiffies is defined in the linker script... */ -void do_timer(struct pt_regs *regs) +void do_timer(unsigned long ticks) { - jiffies_64++; - /* prevent loading jiffies before storing new jiffies_64 value. */ - barrier(); - update_times(); + jiffies_64 += ticks; + update_times(ticks); } #ifdef __ARCH_WANT_SYS_ALARM -- cgit v1.2.3